Latest ArticlesLateral flow immunoassay (LFIA) has become popular in laboratories, at-home testing, and medical diagnostics due to its minimal cost and user-friendliness. Nevertheless, conventional test strips based on colloidal gold can only obtain qualitative or semi-quantitative results with low sensitivity. In this work, Au-Fe3O4 dumbbell-like nanoparticles were synthesized and used as the LFIA labelling marker for highly sensitive colorimetric-photothermal dual-mode detection of SARS-CoV-2 spike(S) protein. The unique dumbbell structure of Au-Fe3O4 NPs makes it possible to combine the best features of both Au NPs and Fe3O4 NPs. The increased surface area of these NPs enhances their LSPR effect and photothermal effect, which achieves signal amplification to increase sensitivity. The Au-Fe3O4 NPs modified with S protein antibody could identify S protein in samples, which were recognized and accumulated on T-line by another antibody, generating color band for qualitative colorimetric detection. The T-line was irradiated by laser to obtain temperature change for quantitative detection of photothermal. In optimized conditions, the detection limit was 1.22 pg/mL, three orders of magnitude more sensitive than colorimetric detection. Finally, the approach was performed on SARS-CoV-2 pseudovirus samples and outperformed traditional colloidal gold strips. This LFIA platform exhibits significant promise for practical implementation, as it can satisfy the need for low-cost, high-sensitivity, and home-based quantitative detection for respiratory infectious diseases.
Artificial macrocycle with high binding selectivity in water is often challenging but urgently needed in various research and application areas. Herein, we report a new water-soluble biomimetic tetralactam macrocycle and realize the ultra-high selectivity to nucleosides over corresponding monophosphate nucleotides by rational modification. The introduction of charged groups at the periphery of endo-functionalized cavity makes the selectivity (guanosine to guanosine 5′-monophosphate) increase remarkably from 100 to 1119. Based on the ultra-high selectivity of biomimetic tetralactam macrocycle, the sensitive CD73 enzyme activity assay was then achieved through product-selective fluorescence indicator displacement assay. Furthermore, the capability of the proposed method for inhibitor screening was successfully displayed.
Tryptophan (Trp) carries a unique heteroaromatic indole side chain and plays a critical role in peptide or protein modification. Herein, we have reported a metal-free photoinduced N-H alkylation strategy using N-aryl glycines for specific modification of tryptophan-containing peptides. The robustness of our approach is demonstrated by its wide substrate scope, excellent isolated yields, as well as almost unobservable side effects. Using this highly efficiently metal-free condition, alkylated Trp-containing peptides can be smoothly assembled. This study provides a reliable and practical tool for the chemo-selective modification of various tryptophan containing oligopeptides.
Selenium is an essential trace element for humans and animals. As the active center of selenoproteins, the addition of selenium is beneficial to enhance the antioxidant ability. However, the high cost limits the application of organic Se in agriculture animal production. Selenized glucose (SeGlu) is a newly invented organoselenium material with good stability, low toxicity and low cost. This assay found that SeGlu was able to increase selenium deposition in liver of newborn broilers, and enhance the antioxidant capacity of liver by elevating the activities of antioxidant enzymes such as total superoxide dismutase and glutathione peroxidase. This paper as the first example clarifying the mechanism of SeGlu to enhance the antioxidant ability of chicks, shows that SeGlu can be used as an organic selenium enrichment additive for early nutrition of poultry. As a cross-discipline study involving chemistry, biology and agriculture animal science, the work may be beneficial for studies in related fields and prompt the development of the selenium science.
Long-term excessive intake of nitrite (NO2−) poses a great threat to human health, needing a simple and fast method to detect NO2− in food. Herein, via a simple and feasible strategy, Mn/Yb/Er triple-doped CeO2 nanozyme (Mn/Yb/Er/CeO2) was synthesized for highly sensitive ratiometric detection of nitrite. By doping Mn, Yb, Er into CeO2 lattice structure, Mn/Yb/Er/CeO2 nanozyme showed enhanced oxidase-like activity, obtaining a higher density of oxygen vacancy and a higher ratio of Ce3+ to Ce4+ than that of CeO2. The 3,3′,5,5′-tetramethylbenzidine (TMB) can be effectively oxidized by Mn/Yb/Er/CeO2 to produce the oxidized TMB (oxTMB), showing a significant absorption signal at 652 nm. Additionally, nitrite can react with oxTMB to produce yellow diazotized oxTMB, which is accompanied by an elevated absorption signal at 445 nm and a decreased absorption signal at 652 nm. Thus, based on the oxidase-mimetic activity of Mn/Yb/Er/CeO2 and the diazotization reaction between NO2− and oxTMB, a ratiometric colorimetric assay was established for NO2− detection in food. Furthermore, by integrating Mn/Yb/Er/CeO2 with a smartphone, a colorimetric smartphone-sensing platform was successfully fabricated for visualization and quantitative detection of NO2−. Notably, this two-detection mode showed excellent sensitivity, selectivity, reliability and practicability in monitoring the NO2− in real samples, impling its great potential for food safety.
The seven-membered ring motifs are found in bioactive pharmaceuticals and a wide range of natural products, including alkaloids and terpenoids, which hold significant importance in synthetic chemistry and has garnered considerable attention from both academia and industry. Despite the challenges faced in the past decade, the total synthesis of natural products incorporating the non-aromatic cycloheptane skeletons remains a compelling pursuit. Recently, numerous elegant strategies for constructing the seven-membered ring system have been successfully developed. This review focuses on the recent advancements in this field from 2017 to April 2023, highlighting key transformations utilized to construct the non-aromatic cycloheptane core structures and serves as a valuable guide for synthetic chemists engaged in the total synthesis of natural products containing seven-membered ring motifs.
The over-exploitation of fossil fuel energy has brought about serious environmental problems. It would be of great significance to construct efficient energy conversion and storage system to maximize utilize renewable energy, which contributes to reducing environmental hazards. For the past few years, in terms of electrocatalysis and energy storage, carbon fiber materials show great advantages due to its outstanding electrical conductivity, good flexibility and mechanical property. As a simple and low-cost technique, electrospinning can be employed to prepare various nanofibers. It is noted that the functional fiber materials with different special structure and composition can be obtained for energy conversion and storage by combining electrospinning with other post-processing. In this paper, the structural design, controllable synthesis and multifunctional applications of electrospinning-derived functional carbon-based materials (EFCMs) is reviewed. Firstly, we briefly introduce the history, basic principle and typical equipment of electrospinning. Then we discuss the strategies for preparing EFCMs with different structures and composition in detail. In addition, we show recently the application of advanced EFCMs in energy conversion and storage, such as nitrogen species reduction reaction, CO2 reduction reaction, oxygen reduction reaction, water-splitting, supercapacitors and ion batteries. In the end, we propose some perspectives on the future development direction of EFCMs.
The hydrosilylation of unsaturated carbon-carbon bonds is one of the most critical reactions in silicone industrial production. The homogeneous Speier's catalyst, Karstedt's catalyst, and other noble metal-based catalysts are widely used. However, simplifying the separation of the homogeneous catalyst from reaction products and reducing the high cost of precious metals is still challenging. This review describes the recent development of heterogeneous catalysts for alkene, alkyne, and allene hydrosilylations, which can effectively solve problems in homogeneous hydrosilylation.
Electrocatalytic nitrogen reduction reaction (NRR) is considered as an attractive approach for ammonia synthesis under mild conditions. A bottleneck of NRR is the exploration of efficient catalysts for accelerating reaction kinetics, among which heterogeneous structures possessing distinct atomic arrangement could modify electronic structure, and therefore altering their NRR activity. Here, we report a facile strategy for fabricating hetero-phase metal oxides derived from metal organic framework that are further integrated with Au nanoparticles as NRR catalysts. The phase composition of zirconia can be easily adjusted by simply changing the reaction temperature, where the monoclinic and tetragonal phases with the roughly close proportions have a distinct interface, leading to a strong interaction between Au and ZrO2. The enhanced interaction renders Au to be more electropositive and facilitates stronger binding to N2. As a result, a remarkable ammonia yield of 22.32 µg h−1 mgcat.−1 and a Faradaic efficiency of 31.92% can be achieved at low overpotential. This work is expected to pave the way for the design of heterogeneous structures and the exploration of hetero-phase nanostructures in boosting the electrocatalytic NRR.
O3-type layered oxide cathodes have been widely investigated due to their high reversible capacities and sufficient Na+ reservoirs. However, such materials usually suffer from complex multistep phase transitions along with drastic volume changes, leading to the unsatisfied cycle performance. Herein, we report a Mg/Ti co-doped O3-type NaNi0.5Mn0.5O2, which can effectively suppress the complex multistep phase transition and realize a solid-solution reaction within a wide voltage range. It is confirmed that, the Mg/Ti co-doping is beneficial to enhance the structural stability and integrity by absorbing micro-strain and distortions. Thus, the as obtained sample delivers an outstanding cyclic performance (82.3% after 200 cycles at 1 C) in the voltage range of 2.0–4.0 V, and a high discharge capacity of 86.6 mAh/g after 100 cycles within the wide voltage range (2.0–4.5 V), which outperform the existing literatures. This co-doping strategy offers new insights into high performance O3-type cathode for sodium ion batteries.
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